Electric cell potting compound and method of making

ABSTRACT

A battery module comprising an electric cell and a potting compound associated with the electric cell. The potting compound is formed of a flame retardant component; a first component having an isocyanate reactive compound and water; and a second component having an isocyanate compound. The potting compound is a foam.

This patent application claims the benefit of or priority to U.S.provisional application No. 62/631,584 filed on Feb. 16, 2018.

FIELD

The present disclosure relates to battery modules that include anelectric cell positioned in a potting compound. More particularly, thepresent disclosure relates to battery modules that include an electriccell positioned in a foam potting compound that contains a flameretardant.

BACKGROUND

In general, potting is the process of partially or completely filling orembedding an enclosure with a material for the purpose of maintainingobjects within the enclosure in spatial relationship to one another andto the enclosure. Potting may be used to provide resistance to shock andvibration. Certain compositions used for potting may be designed forcreating a seal against moisture, solvents, and corrosive agents.

Materials used to form potting compounds vary in hardness from very softto hard and rigid, and are designed to withstand various environments.Potting compounds for use in potting electric cells may be designed toprovide mechanical stability and shock tolerance, for example forbattery modules intended for use in a vehicle. A potting compound thatprovides mechanical stability to an electric cell while adding minimalweight to the battery module is desired. A potting compound for use in abattery module that provides mechanical stability to an electric celland is flame retardant is also desired.

SUMMARY

Disclosed herein is a battery module comprising an electric cell and apotting compound associated with the electric cell. The potting compoundis formed of a flame retardant component; a first component having anisocyanate reactive compound and water; and a second component having anisocyanate compound. The potting compound is a foam after curing.

The potting compound may have at least a V2 level flame resistance asmeasured by the UL 94 Test for Flammability of Plastics. The pottingcompound may have a foam density of less than 0.50 g/cm³. The flameretardant component may be present in an amount of at least 15 wt. %,based on the total weight of the potting compound. The flame retardantcomponent may be present in an amount of at least 30 wt. %, based on thetotal weight of the potting compound. A potting composition configuredto form the potting compound may have sufficient flowability beforecuring to settle at a level height around the electric cell.

The first component may have a viscosity from greater than one to lessthan 100,000 cP. The second component may have a viscosity from greaterthan one to less than 50,000 cP at a temperature from about 25° C. toabout 35° C. The first component may have a viscosity from greater thanone to less than 1,500 cP. The second component may have a viscosityfrom greater than one to less than 1,000 cP at a temperature from about25° C. to about 35° C.

Also disclosed herein is a battery module comprising an electric cellpositioned in a potting compound. The potting compound may be formedfrom the reaction product of a first component having an isocyanatereactive compound; and a second component having an isocyanate compound.The potting compound may further include a blowing agent, and a liquidflame retardant component present in an amount from about 15 wt. % toabout 60 wt. % based on the total weight of the potting compound.

The liquid flame retardant may include a phosphate ester. The isocyanatereactive compound may be a polyether polyol. The isocyanate reactivecompound may have an isocyanate reactive functionality of three or more.The isocyanate compound may have an average isocyanate functionality oftwo or greater.

The first component may have a viscosity from greater than one to lessthan 100,000 cP. The second component may have a viscosity from greaterthan one to less than 50,000 cP at a temperature from about 25° C. toabout 35° C. The first component may have a viscosity from greater thanone to less than 1,500 cP. The second component may have a viscosityfrom greater than one to less than 1,000 cP at a temperature from about25° C. to about 35° C.

Also disclosed herein is a battery module comprising a first electriccell positioned in a polyurethane foam potting compound. The pottingcompound has a density of less than 0.50 g/cm³. The foam pottingcompound has at least a V2 level flame resistance as measured by the UL94 Test for Flammability of Plastics. The potting compound may be formedfrom a potting composition that has sufficient flowability before curingto disperse to a substantially level height between the first electriccell and a battery module case positioned around the first electriccell.

While multiple embodiments are disclosed, still other embodiments of thepresent disclosure will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the disclosure. Accordingly, the drawingsand detailed description are to be regarded as illustrative in natureand not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a battery module, in accordance withcertain embodiments.

FIG. 2 is a top view of a battery module, in accordance with someembodiments.

FIG. 3 is a front view of a battery module, in accordance with someembodiments.

FIG. 4 is a perspective view of a battery module, in accordance withcertain embodiments.

FIG. 5 is a top view of a battery module, in accordance with someembodiments.

FIG. 6 is an exploded view of a battery module, in accordance with someembodiments.

DETAILED DESCRIPTION

Disclosed herein is a potting compound that is low density and is flameretardant. The potting compound has at least a V2 level flame resistanceas measured by the UL 94 Test for Flammability of Plastics. In someinstances, the potting compound has at least a V1 level flame resistanceas measured by the UL 94 Test for Flammability of Plastics. In someembodiments, the potting compound has at least a V0 level flameresistance as measured by the UL 94 Test for Flammability of Plastics.

The potting compound may be formed from a potting composition that isapplied as a liquid and cures to form the potting compound. The pottingcomposition has sufficient flowability before curing to allow thepotting composition to be applied as a liquid around an electric celland then settle at a substantially level height around the electriccell. The potting composition disclosed herein can be applied as aliquid and flow around the electric cell and through the spaces definedbetween adjacent electric cells before curing to form the pottingcompound. The potting compound is useful for potting an electric celland forming a battery module that is lightweight. The potting compoundis useful to pot an electric cell and provide mechanical stability andflame retardancy after curing.

The potting compound may be formed from materials that form foams whencured, including silicones, epoxies, for example a one- or two-componentepoxy resin, or polyurethanes. In some embodiments, the potting compoundincludes a polyurethane foam. The potting compound may be formed from apolyurethane composition that is a liquid before curing, and which curesand hardens as a foam to form the potting compound. In some embodiments,the potting compound is formed from a polyurethane foam that has lowdensity and includes a flame retardant.

As used herein a foam is defined as a substance formed from a bulkmaterial which defines the cavities throughout the substance. Thecavities may be filled with gas, such as air, oxygen, carbon dioxide,nitrogen, or any suitable gas. The cavities form a cellular structurethroughout the bulk material. For example, the potting composition maybe a liquid mixture formed of components that react with each other andrelease a gas that forms bubbles throughout the liquid. The liquidpotting composition hardens when cured to form a solid potting compoundthat is a solid substance having cavities throughout the solidsubstance. The cavities result in the solid substance having a lowerdensity than if the solid substance were completely formed of the bulkmaterial without the cellular structure. The foam can be closed-cell oropen-cell. Closed-cell refers to a foam having cavities that formdiscrete pockets completely surrounded by solid material. Open-cellrefers to a foam having cavities that form pockets that connect to eachother.

It is further contemplated, that in some instances, a low densitypotting compound may be formed with a bulk substance which includesexpanded or unexpanded microballoons, e.g. syntactic foams. For example,solid particles formed from glass or polymeric materials may, be used toform a three dimensional shape, such as a bead or bubble, defining agas-filled center. The beads or bubbles may be distributed throughout abulk substance that can cure and entrap the beads or bubbles, thusdecreasing the overall density of the cured potting compound.

After curing, the potting compound that is a foam has a lower densitythan the density of the potting composition that is a liquid. In someembodiments, the potting compound has a density of less than about 0.60g/cm³, less than about 0.50 g/cm³, less than about 0.40 g/cm³, less thanabout 0.30 g/cm³, less than about 0.20 g/cm³, less than about 0.10g/cm³, or less than about 0.05 g/cm³ after curing. For example, thepotting compound may be a foam having a foam density from about 0.02g/cm³, about 0.05 g/cm³, about 0.10 g/cm³, about 0.20 g/cm³, to about0.30 g/cm³, about 0.40 g/cm³, or about 0.50 g/cm³, or a density betweenany pair of the foregoing values, although potting compounds havingadditional densities are further contemplated.

The potting composition may be a two-part composition formed from afirst component that is reacted with a second component. At least one ofthe first component or the second component may contain a flameretardant. The first component and the second component may be selectedto form a thermoplastic polyurethane component (TPU). After mixing thefirst component and the second component, the potting composition may bea blend of a polyurethane component and a liquid flame retardantcomponent. The first and/or second component may also contain one ormore additional additives.

The First Component

The first component is a liquid at room temperature (between about 25°C. and about 35° C.). For example, the first component has a viscosityfrom greater than 1 to less than 100,000 centipoise (cP), at roomtemperature. In some embodiments, the first component has a viscosityfrom about 100 cP, about 200 cP, about 300 cP or about 400 cP, to about1100 cP, about 1200 cP, about 1300 cP, or about 1400 cP, about 10,000,about 20,000, about 30,000, about 40,000, or as great as 100,000 or aviscosity between any pair of the foregoing values, although componentshaving alternative viscosities are further contemplated.

The first component includes one or more isocyanate reactive compounds.The isocyanate reactive compound may be a compound containing an activehydrogen, for example an amine, an alcohol, or thiol. The firstcomponent includes an isocyanate reactive compound having afunctionality of two or more. Preferred isocyanate reactive compound arethose having a functionality of three or more. Suitable isocyanatereactive compounds are those that are liquid at room temperature.Preferred isocyanate reactive compounds are those that have a lowviscosity at room temperature. For example, suitable isocyanate reactivecompounds may have a viscosity from greater than one to less than about800 cP, less than about 700 cP, less than about 600 cP, or less thanabout 500 cP, at room temperature. Preferred examples of isocyanatereactive compounds include those that have a viscosity of less thanabout 200 cP, less than about 190 cP, less than about 180 cP, or lessthan about 170 cP, at room temperature (between about 25° C. and about35° C.).

The isocyanate reactive compound may be a polyol. The isocyanatereactive compound may be a combination of two or more polyols. Forexample, the isocyanate reactive compound may be a diol polyol, a triolpolyol, tetra polyol or a higher order polyol, and combinations thereof.Preferred examples of polyols that may be used as the isocyanatereactive compound include those that have a low viscosity at roomtemperature.

The polyol may be selected from the group consisting of a polyetherpolyol and a polyester polyol. Suitable polyether polyols include, butare not limited to, polyoxyalkylene polyols such as polyethylene glycol,polypropylene glycol, polytetramethylene glycol, polybutylene glycol,and mixtures and combinations thereof. In some embodiments, a suitablepolyether may have a number average molecular weight (M_(n)) from about200, about 300, about 400, about 600, to about 800, about 1,000, about4,000, or about 6,000, or a molecular weight between any pair of theforegoing values, although polyethers having additional molecularweights are further contemplated.

In some embodiments, suitable polyols may include polyhydroxy ethers,including substituted or unsubstituted polyalkylene ether glycols orpolyhydroxy polyalkylene ethers; polyhydroxy polyesters; the ethylene orpropylene oxide adducts of polyols and the monosubstituted esters ofglycerol; polymer polyols, for example graft polyols containing aproportion of a vinyl monomer, polymerized in situ; and mixtures andcombinations thereof. Further examples of suitable polyols includepoly(diethylene glycol adipate).

In some embodiments, a homopolymer and a copolymer of polyoxyalkylenemay be used. In some embodiments, copolymers of the polyoxyalkylenepolyols may include an adduct of at least one compound includingethylene glycol, propylene glycol, diethylene glycol, dipropyleneglycol, triethylene glycol, 2-ethylhexanediol-1,3,glycerin, 1,2,6-hexanetriol, trimethylol propane, trimethylol ethane,tris(hydroxyphenyl)propane, triethanolamine, triisopropanolamine; andone compound including ethylene oxide, propylene oxide and butyleneoxide.

In some embodiments, a suitable polyester polyol can be formed from thereaction of one or more polyhydric alcohols having from about two toabout 15 carbon atoms with one or more polycarboxylic acids having fromabout two to about 14 carbon atoms. Examples of suitable polyhydricalcohols include ethylene glycol, propylene glycol such as 1,2-propyleneglycol, 1,3-propylene glycol, glycerol, pentaerythritol,trimethylolpropane, 1,4,6-octanetriol, butanediol, pentanedial,hexanediol, dodecanediol, octanediol, chloropentanediol, glycerolmonallyl ether, glycerol mono ethyl ether, diethylene glycol,2-ethylhexanediol, 1,4-cyclohexanediol, 1,2,6-hexanetriol,1,3,5-hexanetriol, 1,3-bis-(2-hydroxyethoxy) propane and similarcomponents.

In some embodiments, the isocyanate reactive compound is present in thefirst component in a weight percent from about 20 percent, about 30percent, or about 40 percent, to about 70 percent, about 80 percent,about 90 percent, or about 100 percent, or a weight percent between anypair of the foregoing values, based on the total weight of the firstcomponent. In preferred embodiments, the isocyanate reactive compound ispresent in the first component in a weight percent from about 20percent, about 25 percent, or about 30 percent, to about 35 percent,about 40 percent, about 45 percent, or about 50 percent, or a weightpercent between any pair of the foregoing values, based on the totalweight of the first component. In embodiments having more than oneisocyanate reactive compound, the total amount of all isocyanatereactive compounds present in the first component have a combined weightpercent from about 20 percent, about 30 percent, or about 40 percent, toabout 70 percent, about 80 percent, about 90 percent, or about 100percent, or a weight percent between any pair of the foregoing values,based on the total weight of the first component.

Suitable commercially available polyols that may be used to form thepolyurethane potting composition include the triol polyether polyol soldunder the trade name POLY-G 30-240 (available from Monument ChemicalGroup, located in Houston, Tex.), the triol polyether polyol sold underthe trade name VORANOL 230-238 (available from the Dow Chemical Company,located in Midland Mich.), and the polyether polyol sold under the tradename ARCOL LHT-240 (available from Covestro AG, located in Leverkusen,Germany).

The Second Component

The second component is a liquid at room temperature (between about 25°C. and about 35° C.). The second component has a viscosity from greaterthan one to less than 50,000 centipoise (cP), at room temperature. Forexample, the second component may have a viscosity from about 40 cP,about 60 cP, about 80 cP or about 100 cP, to about 600 cP, about 700 cP,about 800 cP, about 900 cP, about 1000, about 10,000, about 20,000,about 30,000, or as great as about 50,000 at room temperature (betweenabout 25° C. and about 35° C.), or a viscosity between any pair of theforegoing values, although components having alternative viscosities arefurther contemplated. In a preferred embodiment, the second componenthas a viscosity no greater than 200 cP at room temperature.

The second component includes an isocyanate compound. The isocyanatecompound has an average isocyanate functionality of two or greater.Preferred isocyanate compounds include those that are liquid at roomtemperature including those having a viscosity no greater than 300 cP,no greater than about 200 cP, or no greater than about 100 cP, at roomtemperature (from about 25° C. to about 35° C.). In some embodiments,the isocyanate compound may be a monomer. In some embodiments, theisocyanate compound may be a prepolymer. For example, the isocyanatecompound may be a polymer that is reacted with an isocyanate compound,such as an isocyanate terminated oligomer. In some embodiments, theisocyanate compound may be a polymeric isocyanate.

Suitable isocyanate compounds include, but are not limited to, aromaticisocyanates such as aromatic diisocyanates, or aliphatic isocyanatessuch as aliphatic diisocyanates. In some embodiments, the isocyanatecompound has from one to 10 aliphatic or aromatic groups substituted bythe isocyanate group.

Suitable isocyanate compounds include methylene diphenyl isocyanatecompounds such as diphenyl methane diisocyanate including its isomers,methylene diphenyl diisocyanate (MDI), carbodiimide modified MDI,hydrogenated methylene diphenyl isocyanate (HMDI), hexamethylenediisocyanate (HDI), isophorone diisocyanate (IPID), polymeric methylenediphenyl isocyanate, diphenylmethane-4,4′-diisocyanate,diphenylmethane-2,2′-diisocyanate, diphenylmethane-2,4′-diisocyanate,and other oligomeric methylene isocyanates; toluene diisocyanatecompounds (TDI) including isomers thereof, tetramethylxylenediisocyanate (TMXDI), isomers of naphthylene diisocyanate, isomers oftriphenylmethane triisocyanate, and mixtures and combinations thereof,although additional isocyanates are further contemplated. In someinstances, aliphatic di, tri, and polyisocyanates are also suitableisocyanate compounds, including, for example, hydrogenated aromaticdiisocyanates, aliphatic polyisocyanates, or cycloaliphaticpolyisocyanates, although additional isocyanates are furthercontemplated. Suitable isocyanate compounds that are commerciallyavailable include the modified liquid MDI sold under the trade nameISONATE 143L (available from The Dow Chemical Company, located inMidland, Mich.), or the polymeric MDI sold under the trade name RUBINATEM (available from Huntsman Corporation, located in The Woodlands, Tex.).

In some embodiments, the isocyanate compound is present in the secondcomponent in a weight percent from about 20 percent, about 30 percent,or about 40 percent, to about 70 percent, about 80 percent, about 90percent, or about 100 percent, or a weight percent between any pair ofthe foregoing values, based on the total weight of the second component.In a preferred embodiment, the isocyanate compound is present in thesecond component in a weight percent from about 50 percent, about 55percent, or about 60 percent, to about 70 percent, about 75 percent,about 80 percent, or about 85 percent, or a weight percent between anypair of the foregoing values, based on the total weight of the secondcomponent. In embodiments having more than one isocyanate compound, thetotal amount of all isocyanate compounds present in the second componenthave a combined weight percent from about 20 percent, about 30 percent,or about 40 percent, to about 70 percent, about 80 percent, about 90percent, or about 100 percent, or a weight percent between any pair ofthe foregoing values, based on the total weight of the second component.

Blowing Agent

The potting composition includes a blowing agent. Suitable blowingagents are those that can react with the remaining components of thepotting composition to create pockets of gas in the potting compositionthat form cavities when the potting compound is cured. Chemical blowingagents include water, azodicarbonamide (e.g. for vinyl), hydrazine andother nitrogen-based materials for thermoplastic and elastomeric foams,and sodium bicarbonate for thermoplastic foams. In some embodiments, theblowing agent may be a gas. For example, the blowing agent may be a gasthat is injected into the battery potting composition to create pocketsof gas in the potting composition once the components of the pottingcomposition are mixed. Suitable blowing agents that may be injected intothe battery potting composition include nitrogen or carbon dioxide.

In some embodiments, the blowing agent may be a liquid. In someembodiments, the blowing agent is water. For example, in the case of thepotting compound being formed from polyurethane, water may be includedto react with the polyurethane forming components to form carbon dioxidegas when the polyurethane components are mixed. The carbon dioxide gasforms bubbles in the liquid potting composition. The bubbles formcavities in the polyurethane after it cures and hardens, resulting in afoam potting compound. In some embodiments, the blowing agent is presentin the potting composition at a weight percent from greater than zero,about 0.1 percent, about 0.5 percent, or about 1.0 percent, to about 1.5percent, about 2.0 percent, about 2.5 percent, or about 3.0 percent, ora weight percent between any pair of the foregoing values, based on thetotal weight of the first component. In some embodiments, the blowingagent may be included in the first component. For example, in someembodiments, the blowing agent may be a liquid blowing agent included inthe first component.

The Flame Retardant Component

The potting composition includes a flame retardant component. The flameretardant component is preferably a liquid at room temperature. In someembodiments, the potting composition includes two or more flameretardant components. The flame retardant component may be present inone or both of the first or second components. In some embodiments, thefirst component may include a first flame retardant component and thesecond component may include a second flame retardant component.

Suitable flame retardant components may include those having a viscosityfrom about 30 cP, about 40 cP, about 100 cP, about 200 cP, about 300 cPor about 400 cP, to about 600 cP, about 700 cP, about 800 cP, or about900 cP, or about 2000 cP, or a viscosity between any pair of theforegoing values at room temperature (between about 25° C. and about 35°C.), although liquid flame retardants having alternative viscosities arefurther contemplated. Preferred liquid flame retardant componentsinclude those having a viscosity no greater than about 300 cP at roomtemperature. For example, preferred liquid flame retardant componentsinclude those having a viscosity from about 40, about 60, or about 80,or about 100, to about 150, about 200, about 250, or about 300, or aviscosity between any pair of the foregoing values at room temperature,although flame retardants having additional viscosities are furthercontemplated.

In some embodiments, the flame retardant component includes a phosphateester. The flame retardant component may include a halogenated phosphateester. The flame retardant component may include one or both of abrominated phosphate ester or a chlorinated phosphate ester. Forexample, a suitable liquid flame retardant may be tris(2-chloroisopropyl) phosphate.

The flame retardant component may include other examples of brominatedorganic compounds including brominated diols, brominated mono-alcohols,brominated ethers, brominated phosphates, and combinations thereof.Suitable brominated organic compounds may include tetrabromobisphenol-A,hexabromocyclododecane, poly(pentabromobenzyl acrylate),pentabromobenzyl acrylate, tetrabromobisphenol A-bis(2,3-dibromopropylether), tribromophenol, dibromoneopentyl glycol, tribromoneopentylalcohol, tris(tribromoneopentyl) phosphate, and4,4′-isopropylidenebis[2-(2,6-dibromophenoxy) ethanol].

In some embodiments, a suitable commercially available flame retardantcomponent may be the chlorinated phosphate ester sold under the tradename FYROL PCF (from ICL industrial Products, located in St. Louis,Mo.).

The flame retardant component is present in at least one of the first orsecond component. The flame retardant component may be present in atleast one of the first or second component at a weight percent fromgreater than zero percent, about 10 percent, about 20 percent, or about30 percent, to about 40 percent, about 50 percent, or about 60 percent,about 70 percent, or a weight percent between any pair of the foregoingvalues, based on the total weight of the component (either the first orthe second component) that the flame retardant component is present in.In some embodiments, the flame retardant component may be present inboth the first component and the second component.

In some embodiments, the total amount of the flame retardant componentin the potting composition is a weight percent from about 15 percent,about 20 percent, about 25 percent, or about 30 percent, to about 40percent, about 45 percent, about 50 percent, about 55 percent, or about60 percent, or a weight percent between any pair of the foregoingvalues, based on the total weight of the potting composition. Forexample, a first flame retardant component may be present in the firstcomponent at a weight percent from about 30 percent, about 35 percent,or about 40 percent, to about 45 percent, about 50 percent, or about 55percent, or a weight percent between any pair of the foregoing values,based on the total weight of the first component; and a second flameretardant component may be present in the second component at a weightpercent from about 20 percent, about 25 percent, or about 30 percent, toabout 35 percent, about 40 percent, or about 45 percent, or a weightpercent between any pair of the foregoing values, based on the totalweight of the second component.

It has been found that in some instances, a suitable amount of flameretardant component in the potting composition will provide suitablelevels of flame retardancy without compromising other desirablecharacteristics. For example, in some instances the stiffness, hardness,flexibility, durability, or structural resilience of certain foamcompounds may be unsuitable when high levels of flame retardant ispresent. In some embodiments, a suitable weight percent of flameretardant component in a polyurethane foam to provide a suitable levelof flame retardancy and providing a suitably strong potting compound maybe an amount of from about 25 percent, about 30 percent, or about least35 percent, to about 40 percent, about 45 percent, or about 50 percentbased on the total weight of the potting composition.

Optional Additional Additives

The potting composition may optionally include additional additives,either as separate components or mixed into one or more of thecomponents described above to form the first and/or second component.The optional additional additives, may be present in the pottingcomposition at a weight percent from greater than zero, about 0.1, about0.5, or about one, to about five, about 10, about 20 percent, or about30 percent, based on the total weight of the potting composition, or aweight percentage between any pair of the foregoing values. The weightpercentage of the option additional additives may be applied to thecombined total of all additional additives present or to each additionaladditive separately.

Some examples of additional additives that may be added to either orboth of the first or second components include, but are not limited tocrosslinkers, chain extenders, humectants, thixotropy, nucleatingagents, surfactants, diluents, anti-settling agents, flame-retardantenhancers, and components and combinations thereof. In some embodiments,the optional additional additives include waxes, release agents,antioxidants, reinforcing fillers, pigments, heat stabilizers, UVstabilizers, plasticizers, rheology modifiers, processing aids,lubricants, mold release agents, or component or combinations thereof.Suitable reinforcing fillers include mineral fillers and glass fibers.

Further examples of additional components include catalysts. In theexample of a polyurethane potting composition, any conventional catalystknown to those of skill in the art can be used to react the isocyanatecompound with the isocyanate reactive compound and the remainingcomponents. Suitable catalysts include, but are not limited to triolcatalysts, tetra polyol catalysts, or tertiary amine catalysts. Furtherexamples of suitable catalysts include the various alkyl amines, alkylethers or alkyl thiol ethers, such as those of bismuth or tin whereinthe alkyl portion has from one to about 20 carbon atoms. Some examplesinclude bismuth octoate, bismuth laurate, and the like. Other catalystsinclude the various tin catalysts such as stannous octoate, dibutyltindioctoate, dibutyltin dilaurate, and the like.

In the example of a polyurethane potting composition, the amount of acatalyst present may from greater than zero, about 0.02, about 0.05, orabout 0.1, to about 0.25, about 0.75, or about one percent, based on thetotal weight of the battery potting composition, or a weight percentbetween any pair of the foregoing values. In some embodiments, a crosslinker or humectant may be present in the potting composition at aweight percent from greater than zero, from about 0.1, about 0.5, orabout one, to about five, about seven, or about 10 percent; based on thetotal weight of the potting composition, or a weight percent between anypair of the foregoing values. In some embodiments, a surfactant, forexample suitable for stabilizing the foam structure or for helping withwet out, may be present in the potting composition at a weight percentfrom greater than zero, from about 0.1, about 0.5, or about one, toabout two, about three, or about four percent, based on the total weightof the potting composition, or a weight percentage between any pair ofthe foregoing values. In some embodiments, a nucleating agent may bepresent in the battery potting composition at a weight percent fromgreater than zero, from about 0.1, or about 0.5, to about one, about1.5, or about two percent, based on the total weight of the batterypotting composition, or a weight percent between any pair of theforegoing values.

The first and second component are combined to form the pottingcomposition having the flame retardant component. For example, in theembodiment of a polyurethane used to form the foam potting composition,the first and second component are mixed to form the polyurethane. Thepolyurethane may be present in the potting composition at a weightpercent from about 30 percent, about 40 percent, or about 50 percent, toabout 60 percent, about 70 percent or about 80 percent, or a weightpercent between any pair of the foregoing values, based on the totalweight of the potting composition. In some instances, one technique forcalculating the amount of polyurethane present in the pottingcomposition is to use a theoretical calculation based on the startingcomponents. That is, the weight percentage of all the components thatwould form the polyurethane (if the starting components were to producea 100% yield of polyurethane) are added up. The total amount of thosecomponents is then taken as a weight percent of the total amount of thepotting composition to arrive at the polyurethane weight percent in thepotting composition.

Any known processes to react the first component with the secondcomponent may be used. In embodiments comprising a polyurethane pottingcomposition, any known processes for combining the first and secondcomponent to make the polyurethane foam may be used. In someembodiments, the process for combining may be a “one-shot” process whereall the reactants are mixed in a mixing vessel, such as a bucket or areactor, and reacted and/or applied.

In some embodiments, the ratio of the weight amount of the isocyanatecompound to the total equivalent weight amount of the isocyanatereactive component may be from about 0.60, about 0.65, about 0.70, orabout 0.75, to about 0.80, about 0.85, about 0.90, or about 0.95, or aratio between any pair of the foregoing values. In some embodiments, theratio of isocyanate compound to isocyanate reactive compound is chosensuch that an excess of reactive isocyanate equivalents in relation tothe total number of isocyanate reactive groups on the isocyanatereactive compound is used.

In some embodiments, the polyol of the first component may be present inthe potting composition in a weight percent of from about 10 percent,about 20 percent, about 30 percent or about 40 percent, to about 50percent, about 60 percent, about 70 percent, or about 80 percent, or aweight percent between any pair of the foregoing values.

FIG. 1 is a perspective view of an example battery module 10. As shownin FIG. 1, the battery module 10 includes an electric cell 20 and abattery case 22. In some embodiments, the electric cell 20 may bepositioned within the battery case 22 and potted in a potting compound24. The electric cell 20 may be any suitable shape which generally has abottom 30, a top 32 and a length defined therebetween. The battery case22 may be any suitable shape for retaining the electric cell 20, andwhich generally has a bottom 36, a top 38, and a wall 40 definedtherebetween. The bottom 36 of the battery case 22 defines an innersurface and an outer surface; the wall 40 of the battery case defines aninner surface and an outer surface. The battery case 22 defines anenclosed space having an internal volume. The potting compound 24 ispositioned within the battery case 22 and occupies a portion of theinternal volume of the battery case 22. The potting compound 24generally has a top 42, a bottom 44, and a height defined therebetween.

FIG. 2 is a top view of the battery module 10, shown in FIG. 1 As shownin FIG. 2, the battery case 22 forms an enclosed space that is largeenough to surround the electric cell 20 and other components such aswires or connections. The enclosed space defines the internal volume ofthe battery case 22. The bottom 36 of the battery case 22 may be closed,and contain any contents of the enclosed space. The top 38 of thebattery case 22, may define an opening. The top 38 and/or the openingmay be shaped and sized to receive a cover that can be closed toseparate the internal volume of the enclosed space from the outside ofthe battery case 22. The cover may be configured to seal off theinternal volume of the enclosed space from the outside of the batterycase 22 to prevent entry of potential hazards such as fluids or flames.The battery case 22 may be designed and configured to provide mechanicalor structural support to the electric cell 20. The battery case 22 mayalso be configured to provide protection from moisture, heat, cold, orany other potential factors that may cause damage to the electric cell20.

As shown, in one possible arrangement, the electric cell 20 may beshaped as a cylinder. In further examples, the electric cell 20 may beformed into any suitable shape or size, as the need may be, such as acube, sphere, pyramid, etc. The electric cell shown in FIG. 1 is shapedas a cylinder having the bottom 30, the top 32, and a wall extendingbetween the bottom 30 and the top 32. The bottom 30 may be a positiveterminal, or may be a negative terminal of the electric cell 20,depending on the desired orientation. As shown, the bottom 30 of theelectric cell 20 is positioned in the potting compound 24. The pottingcompound 24 occupies a portion of the internal volume of the batterycase 22 and extends a substantially equal distance at various pointsalong the wall 40 from the bottom 36 of the battery case 22 toward thetop 38.

Electric cells may be used to form a battery. For example, multipleelectric cells may be combined to form a single battery that has ahigher voltage or amperage than a single electric cell.

FIG. 3, is a front view of a battery module 50 that includes electriccells 52. Each of the electric cells 52 has a bottom 60, a top 62, andwall therebetween defining a length. The electric cells 52 may bepositioned within a battery case 54. The electric cells 52 define a gap80 between each electric cell and an adjacent electric cell. The gap 80has a width. The battery case 54 has a bottom 66, a top 68 and a wall 70therebetween. The bottom 66, and the wall 70 define an enclosed space.The enclosed space of the battery case 54 defines an internal volume.The internal volume of the battery case 54 has a suitable volume toreceive the electric cells 52 and a potting compound 56. The pottingcompound 56 has a bottom 82, a top 84, and a height 86 therebetween. Thebottom 82 of the potting compound 56 is adjacent to the inside surfaceof the bottom 66 of the battery case 54. As shown, the top 84 of thepotting compound 56 is between the bottom 66 and the top 68 of thebattery case 54. Typically, the top 84 of the potting compound 56 islower than the top 62 of the electric cells 52, although it isenvisioned that in an alternative arrangement, the top 62 of theelectric cells 52 may be lower than the top 84 of the potting compound56.

As shown, multiple electric cells 52 may be arranged in close proximityto each other, with each of the electric cells 52 oriented withsimilarly charged terminals pointed in the same direction. Wires may beattached to the ends of the electric cells 52. The wires may be combinedin electric communication such that the electric current from theelectric cells 52 is combined, for example to form a battery having acombined current or voltage. The battery module 50 may be used to powerany of a number of applications, such as a household appliance, outdoorelectrical equipment, or a vehicle such as a car or a boat.

To combine the electric cells 52 to form a battery, the electric cells52 are connected with wires that conduct an electric current from theelectric cells 52. The electric cells 52 are often arranged next to eachother, for example in rows or stacked, to form an orderly arrangementfor ease of use and/or for connecting the wires to the electric cellterminals. In the interest of conserving space, and to form a compactbattery, the electric cells 52 may be positioned in close proximity toeach other. For example, the electric cells 52 may be arranged in rowsor as a grid, with the positive and negative terminals oriented in thesame direction. The electric cells 52 may be positioned in an orderedarrangement and contained within the battery case 54, although it isenvisioned that in some instances, a battery module may be formedwithout a battery case 54. For example, the electric cells 52 could beheld together using an alternative securing device, such as a wire,string, band, etc. to hold the electric cells 52 in a bundle, forexample.

In some instances, it may be desired to have a battery that is portable,for instance in the case of a battery to start an ignition for, or topower a vehicle, such as a motorcycle, a car, or a boat, as someexamples. In instances where the battery is desired to be portable, itis typically preferred to provide a battery that is structurally stableand made to with stand forces such as shock and/or vibrations. In someinstances, it is also desired to provide a battery that is made towithstand extreme temperatures, including temperatures outside thenormal operating temperature of the battery. For example, in someinstances, the battery may be subjected to high heat, and possibly openflames. One possible source of flames, may be one or more of theelectric cells, for instance as a result of an electric short or if thestructure of the electric cell wall is compromised. One example devicethat may be used to protect the electric cells 52 is the pottingcompound 56. The potting compound 56 may be associated with the electriccells 52, such as positioned around the electric cells 52 along one ormore of the top, the bottom, or the wall of the electric cell. Theelectric cell or electric cells 52 may be encased or embedded in thepotting compound 56 which holds the electric cells 52 in spatialrelationship to one another and/or in spatial relationship to thebattery case 54.

As shown in FIG. 3, the electric cells 52 are positioned in the pottingcompound 56. The potting compound 56 is positioned around each of theelectric cells 52. In instances where the battery contains multipleelectric cells 52, the potting compound 56 can be positioned around eachelectric cell, and in the gap 80 or spaces defined between individualelectric cells 52. In instances where the battery is contained withinthe battery case 54, the potting compound 56 may be positioned betweenthe electric cell or electric cells 52 and the battery case 54. Thepotting compound 56 may be positioned to provide suitable structural ormechanical support to the electric cells 52.

In some instances, the electric cells 52 may be positioned with asuitable distance between adjacent electric cells 52 such thatindividual electric cells 52 are thermally and/or fluidly isolated fromeach other in the event of a leak or fire. In some instances, theelectric cells 52 may be positioned with a suitable distance betweenadjacent electric cells 52 such that a suitable thickness of pottingcompound 56 is positioned between adjacent electric cells 52 to providesufficient shock dampening to prevent damage to the electric cells 52.The size of the space or gap 80 between adjacent electric cells 52and/or the battery case 54 can be selected based on a number ofvariables, including but not limited to, the size and/or weight of eachelectric cell, the operating temperature of each electric cell, thedimensions of each electric cell, and the intended use of the batterymodule 50. In some examples, the size of the space between adjacentelectric cells may be from greater than 0 mm, about 0.25 mm, about 0.50mm, about 0.75 mm, to about 1.0 mm, about 1.5 mm, or about 2.0 mm, or alength between any pair of the foregoing values, although batterymodules having additional configurations are further contemplated. Insome examples, the size of the space between an electric cell and thebattery case may be from greater than 0 mm, about 1.0 mm, about 2.0 mm,about 3.0 mm, to about 10 mm, about 12 mm, or about 14 mm, althoughbattery modules having additional configurations are furthercontemplated.

In some embodiments, the potting compound 56 may be formed by firstshaping a material such as a potting composition into a suitable shapewith spaces defined by the potting compound 56 for holding one or moreelectric cells 52. The potting compound 56 may be formed by shaping apotting composition with a size and shape such that the potting compound56 is positioned within the battery case 54 and defining one or morespaces to hold one or more electric cells 52 positioned in the spaces.

In some embodiments, the potting compound 56 may be formed by firstarranging the electric cells 52 into the desired final position, forexample, held together with wire or within the battery case 54. Theelectric cells 52 may be held in place in spatial relationship with oneanother using a mold or a scaffolding. The electric cells 52 may be heldin place and positioned within a mold or other encasing surrounding theelectric cells 52. In further examples, the electric cells 52 may bearranged in a desired final position in spatial relationship to oneanother and placed within the battery case 54, for example resting onthe inside surface of the bottom 66 of the battery case 54. Once thedesired arrangement of the electric cells 52 is attained, the pottingcompound 56 may be formed by flowing a potting composition around theelectric cells 52 and through the gap 80 or spaces defined betweenadjacent electric cells 52. The potting composition may be applied as aliquid such that the potting composition flows through the gap 80defined between adjacent electric cells 52 and between the electriccells 52 and the wall 70 of the battery case 54. As describe above, thepotting composition may be configured to be applied as a liquid whichhardens into a solid after being applied and forms the potting compound56. In some embodiments the potting composition may be reactive suchthat the potting composition is applied as a liquid that flows aroundthe electric cells 52 and through the gap 80 defined between adjacentelectric cells 52 and then hardens after the completion of the reaction.

The potting composition can flow through the gap 80 between adjacentelectric cells 52 and settle at a level height around the electric cells52 and in the gap 80 or spaces defined between the electric cells 52.For example, referring to FIG. 3, the potting composition may be pouredinto the battery case 54 having the electric cells 52 arranged within.The liquid potting composition has sufficient flowability before curingto permit the liquid potting composition to flow through the spacesdefined by the gap 80 between the adjacent electric cells 52 and/orbetween an electric cell and the battery case 54. The liquid pottingcomposition has sufficient flowability to settle at a substantiallylevel height before curing to form the potting compound.

As used herein flowability refers to the ease with which a substancewill move under a certain set of conditions. Some of these conditionsmay include the temperature of the substance, the viscosity of thesubstance, or the size of the space through which the substance can flowthrough. For example, for the potting composition that is a liquid, theflowability of the liquid governs how it will behave when poured and howwell it flows between adjacent electric cells and/or the between anelectric cell and the battery case.

In a preferred embodiment, the potting composition has sufficientflowability such that the potting composition can be poured around anelectric cell or the electric cells 52 and settles at a substantiallylevel height around the electric cell or electric cells 52 before thepotting composition hardens to form the potting compound 56. That is,the potting composition has sufficient flowability to disperse to aheight 86 that is substantially the same at various locations around theelectric cells 52 (e.g. throughout the battery case 54) before curing toform the potting compound.

In some embodiments, to determine a substantially level height, theheight 86 of the potting compound 56 can be measured from the bottom 82of the potting compound to the top 84 of the potting compound 56. Thisheight can be measured at various locations throughout the pottingcompound 56, for example near the wall of the battery case 54, andtowards the center of the battery case 54, such as equidistant from twoopposing sides of the case. As used herein, a substantially level heightmeans that measurements of the height 86 of the potting compound atvarious locations are within 20 percent of one another.

In some instances, a test for determining a substantially level heightof the potting compound 56 may be as follows. For a battery, such as thebattery module 50, having electric cells 52 arranged next to each other,if the electric cells 52 are the same length, and are positioned thesame distance from the bottom and/or top of the battery case 54, thepotting compound is at a substantially level height if the pottingcompound 56 is approximately the same distance along the length of eachof the electric cells 52. As used herein, approximately the samedistance is defined as each of the measurements of distance are within20 percent of one another In some instances, this test may be used todetermine a substantially level height of the potting compound 56 whenthe average size of each gap 80 between adjacent electric cells 52 is,for example, from about one mm to about three mm wide.

Having a potting composition having sufficient flowability to form asubstantially level height forms a potting compound that encapsulateseach of the electric cells at substantially the same height. Thisprovides a consistent amount of encapsulation around each of theelectric cells. This may ensure suitable encapsulation of the electriccells 52 to ensure suitable level of protection, such as a suitableamount of structural stability and/or a suitable amount of flameretardant to contain a fire or flames. Having a potting compound havinga substantially level height may help the weight of the battery module50 to be balanced throughout the battery module 50. Suitable balance, orweight distribution, helps the battery module 50 to remain stable, forexample when used in a moving vehicle. A suitably balanced batterymodule may be preferred for use in a vehicle, as it may have less of atendency to rock or tilt in response to external forces, such as side toside, or front to back, acceleration.

Having a battery module that is low weight may be preferred, as this maymake the battery module more portable, and may reduce the amount ofenergy required to move the battery module. For example, in an electricvehicle, it may be advantageous to have a lighter battery module thatcan produce the same amount of power as a heavier embodiment. One optionfor accomplishing this may be to use the same type and number ofelectric cells, but reduce the weight of other components. Reducing thedensity of the potting compound may help to reduce the overall weight ofthe potting compound, without reducing other desirable qualities. Havingthe flame retardant component also helps reduce the likelihood of anuncontrolled fire from the battery module.

After being fully cured, the potting compound, may have a certain degreeof elasticity, thereby buffering shock or vibrations imparted to thebattery module when the battery module is in use. This may help preventsafety problems caused by collision among the electric cells, and/ordetachment of the electric cells from the wires.

The cured potting compound may have a certain degree of porosity,controlled such that if one electric cell is involved in a safetyproblem and leaks, any leaking material such as fluid or gas will becontained and isolated by the potting compound positioned among theadjacent electric cells, so as to improve the safety performance of thebattery module. In addition, the battery module has the advantages ofsimple structure, low density, small size, and low cost.

A potting compound that has a low density, contains a flame retardant,and that is a foam is disclosed. The potting compound is suitable foruse in forming a battery module. A potting composition having suitableflowability to form the potting compound having a substantially levelheight throughout the battery module is also disclosed.

FIG. 4 is a perspective view of an example battery module 100. As shownin FIG. 4, the battery module 100 includes an electric cell 120 and abattery case 122. In some embodiments, the battery module 100 includesmore than one electric cell 120. The electric cell 120 may be anysuitable shape which generally has a bottom 130, a top 132 and a lengthdefined therebetween. The battery case 122 may be any suitable shape forpositioning the electric cell 120 within the battery case 122. Thebattery case 122 may be any suitable three dimensional shape whichgenerally has a bottom 136, a top 138, and a wall 140 definedtherebetween. The bottom 136 of the battery case 122 defines an innersurface and an outer surface; the wall 140 of the battery case 122defines an inner surface and an outer surface. The battery case 122defines an enclosed space having an internal volume.

As shown, the electric cell 120 may be positioned within the batterycase 122. As also shown, the electric cell 120 is associated with apotting compound 124. The potting compound 124 is positioned within thebattery case 122 and occupies a portion of the internal volume of thebattery case 122.

In some embodiments, the battery case 122 forms an enclosed space thatsurrounds the electric cell 120 and other components such as wires,terminals, or connections. The enclosed space defines the internalvolume of the battery case 122. The top 138 of the battery case 122, maydefine an opening. The top 138 may be shaped and sized to receive acover that can be closed to separate the internal volume of the enclosedspace from the outside of the battery case 122. The battery case 122 maybe configured to provide mechanical or structural support to theelectric cell 120. The battery case 122 may be configured to provideprotection from potential damage to the electric cell 120, e.g.moisture, heat, cold, chemicals, shock, vibration, puncturing, orflames. In some embodiments, the battery case 122 may be configured toreceive the potting compound 124 relative to the electric cell 120,including e.g., below an electric cell 120, between a first and anadjacent electric cell 120, above an electric cell 120, or between theelectric cell 120 and the wall 140 of the battery case.

In some embodiments, a process for positioning the potting compound 124in relation to the electric cell 120 includes first positioning theelectric cell 120 inside the battery case 122. One or more electriccells 120 can be positioned together in the battery case with a gap 180defined between adjacent electric cells 120. In some embodiments, a gap180 may also be defined between the electric cell 120 and the wall 140of the battery case 122. In some examples, the potting compound 124 canbe prepared in a separate container and then poured into the batterycase 122. For example, the components of the potting compound 124 can bemixed to form a composition that is curable to form a foam, and then thefoam can applied to the top 132 of the electric cell 120. The pottingcompound 124 can be added such that a layer of potting compound 124having a thickness is disposed over the top 132 of the electric cell120. In some embodiments, the potting compound 124 can be positioned inthe gap 180 between adjacent electric cells 120. The potting compound124 can be positioned in the gap 180 between the wall 120 and theelectric cell 120. The potting compound 124 can be positioned such thata space is defined between the top of the potting compound 124 and thetop 138 of the battery case 122. In some embodiments, an amount ofpotting compound 124 can be cured into a suitable preformed shape, andthe preformed shape can be added into the battery case 122 in a suitableposition relative to the electric cell 120.

FIG. 5 is a top view of an example battery module 200. The batterymodule 200 includes electric cells 220 positioned adjacent to oneanother. As shown in FIG. 5, the electric cells 220 are positionedwithin a battery case 222 that has a top 238. The battery case 222defines an internal volume. As shown, the battery case 222 is sized suchthat the electric cells 222 can be positioned within the internal volumeof the battery case 222 with a space between the top 232 of the batterycase 222 and the top 232 of the electric cells 220. Also shown is apotting compound 224 positioned within the internal volume of thebattery case 222. As shown, the potting compound 224 has a generallyplanar shape and extends along the top 232 of the electric cells 220.The potting compound 224 can be configured such that the terminals 290of the electric cells 220 are accessible to a user. In some embodiments,the electric cells 220 include terminals 290 positioned on a top 232 ofthe electric cells 220. The potting compound 224 can be positionedaround the terminals 290 and between the top 232 of the electric cells220 and the top 238 of the battery case 222.

In some embodiments, a process for positioning the potting compound 224in relation to the electric cells 220 includes first positioning theelectric cells 220 inside the battery case 222. The potting compound 224can be prepared in a separate container and then poured into the batterycase 222. A suitable amount of potting compound 224 can be added suchthat a layer of potting compound 224 having a thickness is disposed atleast one of over the top 232 of the electric cells 220 or in betweenadjacent electric cells 220. In some embodiments, the potting compound224 can be added such that the layer of potting compound 224 has athickness suitable to cover the tops 232 of the electric cells 220 withthe terminals 290 protruding through the thickness of the pottingcompound 224. The potting compound can maintain the electric cells 220in spatial relationship with each other, e.g. by holding the electriccells 220 in relation to each other such as by potting or encapsulatingthe terminals 290.

FIG. 6 is an exploded view of an example battery module 300. The batterymodule 300 includes electric cells 320 positioned adjacent to oneanother. In some embodiments, the battery module 300 includes a batterycase 322. The electric cells 220 are shown with terminals 290 positionedon a top 232 of the electric cells 220. Also shown is a potting compound324 associated with the electric cells 320. As shown in FIG. 6, theelectric cells 320 can have a generally planar shape. As shown, asection of the potting compound 224 has a generally planar shape. Insome configurations, a section of potting compound 324 can be positionedin between adjacent electric cells 320. For example, a section ofpotting compound 324 can have a planar shape and be positioned parallelto the plane of the electric cells 320.

In some embodiments, a process for positioning the potting compound 324in relation to the electric cells 320 includes first positioning theelectric cells 320 in spatial relationship to one another and then thepotting compound 324 can be positioned into a space defined betweenadjacent electric cells 320. For example, the potting compound 324 canbe poured into and cure in the space between adjacent electric cells320. As a further example, the potting compound 324 can be cured andformed into a preformed section which can then be positioned in thespace between adjacent electric cells 320. A suitable amount of pottingcompound 324 can be provided such that a section of potting compound 324having a suitable thickness is disposed between adjacent electric cells220. In some embodiments, a section of potting compound 224 can beprovided such that the section of potting compound 324 has a thicknesssuitable to provide a suitable level of flame resistance. In someembodiments, the potting compound 320 can maintain the electric cells320 in spatial relationship with each other, e.g. absorbing shock orvibration of the battery module 300.

EXAMPLES

The following non-limiting examples are included to further illustratevarious embodiments of the instant disclosure and do not limit the scopeof the instant disclosure.

Test Methods:

Viscosity Test

The viscosity is measured with a Brookfield Viscometer model RVF (fromAMETEK Brookfield of Middleboro, Mass.), at a spindle speed of 20 rpmand at a temperature of 25° C. (77°±2° F.). The spindle used is eithernumber 1 (up to 500 cps), number 2 (up to 2000 cps), or number 5 (up to20,000 cps) depending on the composition being tested.

Foam Density Measurement.

The weight of an empty measuring device, in this case a measuring cup,was recorded to within 0.1 gram. The maximum volume of the measuringdevice was measured by filling the measuring device with water andrecording the amount of water required to fill the internal volume ofthe measuring device in milliliters. The various components were weighedand add to the measuring device.

The components for producing the foam were mixed vigorously for 15-20seconds. The sides and bottom of the measuring device were thoroughlyscraped to ensure all the components reacted. The measuring device wassharply rapped by tapping measuring device on a hard surface to levelthe liquid. The measuring device was placed on a level surface and thefoam was allowed to free rise undisturbed. The foam was allowed to cureand cool for 60-70 minutes. After curing, the top of the foam bun levelwas cut level with the top of the measuring device using a flat tool, inthis case a knife or saw.

The measuring device containing the remaining foam was weighed, theweight in grams was recorded. The weight of the empty measuring devicewas subtracted from the weight of the measuring device containing theremaining foam to obtain the weight of the foam. The density wascalculated by dividing the weight of the foam by the volume of themeasuring device.

Flowability Test

The composition to be tested is mixed with hand mixing, with a stir timeof from 20 to 25 seconds. Then from 65 to 70 grams of a sample of thecomposition to be tested is poured into one side of a container havingdimensions of 8 cm by 15 cm by 9 cm container which has 26 of type 18650cylindrical battery cells standing upright in the container. The test iscarried out at an ambient temperature that is from 21° C. to 24° C.(about 70° F. to about 75° F.).

The composition is observed with the naked eye as it flows between thecylindrical battery cells. The level that the composition settles atwhen cured is given a rating of unacceptable, acceptable, good, and verygood depending on how well it cures at an even planar level around thebattery cells. “Very good” corresponds to a height around the batterycells that is less than 10% in variation at tested locations within thecontainer.

Burn Test

The burn test was conducted in accordance with the UL 94 Test forFlammability of Plastic, Vertical Burning Test method. Burn test samplebars were prepared in a mold having the following dimensions: 125 to 152mm long by 13 mm wide and 9.5 mm thick or 6.35 mm thick. The foam wasallowed to cure in the mold for 8 to 12 hours before removing. Aftermolding, the sample bars were conditioned at 25±2° C. and 50±5% RH for aminimum of 48 hours before testing.

The material was rated V-0 if the individual test specimen extinguishedwithin 10 seconds after the test specimen was removed from the flame ofthe burner, and the total after-flame time for a set of five specimenswas within 50 seconds and there was no ignition of the cotton indicator.The V-1 and V-2 rating required that the individual test specimenextinguished within 30 seconds after removal of the test specimen fromflame of the burner and the total after-flame time for a set of fivespecimens was within 250 seconds. The V-2 rating allowed the cottonindicator to be ignited by flaming particles.

An example process for forming the potting compound is described. Thissame process was used for all the sample potting compounds, with theamounts of each component listed in Table 1 below.

First and Second Component Forming Process

To form the first component, a liquid polyether triol was first added toa mixing vessel. The mixing was started while the liquid polyether triolwas being added to the mixing vessel. The mixer speed was between 25 and30 rpms as the liquid polyether triol was being added. The mixer speedwas increased to between 600 and 800 rpms once all the liquid polyethertriol was added.

In the samples where they were included, a liquid glycerin, atriethanolamine, a polyether, and an antisettling agent were then addedto the mixing vessel. In the samples where they were included, athixotrop (fumed silica), a nucleating agent, a brominated flameretardant component, and flame retardant enhancer (antimony trioxide)were then added to the mixing vessel. The contents of the mixing vesselwere mixed from about 15 to about 20 minutes.

Distilled water was then added to the mixing vessel. In the sampleswhere they were included, while the contents of the mixing vessel werebeing mixed, a tertiary amine catalyst and surfactant were added. Aphosphate ester flame retardant was then added. The contents of themixing vessel were mixed for about 30 minutes to form the firstcomponent. After about 30 minutes, the mixing was stopped, and the firstcomponent was emptied from the mixing vessel.

To form the second component, liquid isocyanate was added to a mixingvessel. The liquid isocyanate was mixed at a mixer speed from 25 to 30rpms while being added to the mixing vessel. In samples having a flameretardant included in the second component, a phosphate ester flameretardant was then added to the mixing vessel. The contents of themixing vessel were mixed for 15 to 20 minutes to form the secondcomponent. After 15 to 20 minutes, the mixing was stopped, and thesecond component was emptied from the mixing vessel.

Potting Composition and Potting Compound Forming Process

Suitable portions of the First Component and Second Component werepoured into a mixing container. The mixing container used was largerthan the amount of total material being mixed to allow for vigorousmixing. For example, for 75 grams of total material a suggested minimumsize of container would be a 150 ml. container for mixing.

The higher density component was placed into the mixing container firstand then the second component was gently added on top of the firstcomponent. This helped limit pre-reaction of the materials to just areaction at the interface. The sides and bottom of the individualmeasuring containers were scraped to ensure nearly all the measuredmaterials were added to the mixing container.

A timer was started and the contents of the mixing container werevigorously mixed for 20 to 30 seconds with a flat sided stir utensiluntil the material was homogeneous and uniform in appearance. The sidesand bottom of the mixing container were scraped during the mixing. Aftermixing, the contents of the mixing container were immediately pouredinto a mold.

To form the non-flame retardant samples, substantially the same stepswere used as described for the flame-retardant material. However, noflame retardant was added to either the first or the second component.

The Comparative Examples and Samples 1 to 10 were prepared with thefollowing components, given with the trade designation and supplierwhere applicable, and in the amounts set forth in Table 1: 2000M_(n) PPGdiol polyether polyol (low viscosity polyol-EO Capped) (POLY G 55-56,available from Monument Chemical Group, of Houston, Tex.); glycerin99.5% (triol crosslinker/humectant) (available from the Dow ChemicalCompany, of Midland, Mich.); triethyanolamine 99% (triolcrosslinker/humectant/catalyst) (available from the Dow ChemicalCompany, of Midland, Mich.); fumed silica (thixotrop) (AEROSIL 200,available from Evonik industries, of Essen, Germany); zinc stearate(nucleating agent) (NB-60, available from PMC Group, of Memphis Tenn.);zinc borate (flame retardant) (ZB-467, available from LanxessAktiengesellschaft, of Cologne, Germany),ethylenebistetrabromophthalimide (brominated flame retardant) (SAYTEXBT-93, available from Albemarle Corporation, of Baton Rouge, La.);distilled water (foam blowing agent); 1,4-Diazabicyclo[2.2.2]octanesolution (tertiary amine catalyst) (DABCO 33 LV, available from EvonikIndustries, of Essen, Germany); titanium dioxide (colorant/nucleatingagent); tertiary amine catalyst (DABCO 8154, available from EvonikIndustries, of Essen, Germany); 700 M_(n) PPG triol polyol) (lowviscosity polyol) (POLY G 30-240, available from Monument ChemicalGroup, of Houston, Tex.); 700 M_(n) polyether poyol (polypropyleneoxide-based triol) (ARCOL LHT-240, available from Covestro, ofLeverkusen, Germany); four-functional polyether polyol (POLY-Q 40-800E,available from Arch Chemicals, Inc. of Norwalk, Conn.); 280 M_(n)amine/PPG tetra polyol (tetra crosslinker/humectant/catalyst) (VORANOL800, available from The Dow Chemical Company, of Midland, Mich.);polyether polyol (VORANOL 230-238, available from The Dow ChemicalCompany, of Midland, Mich.); silicone surfactant (foam cell surfactant)(VORASURF DC 5160, available from Dow Chemical Company); halogenatedphosphate ester (flame retardant) (FYROL PCF, available from ICLIndustrial Products, of St. Louis, Mo.); trimethyl pentanyldiisobutyrate (viscosity diluent) (EASTMAN TXIB, available from EastmanChemical Company, of Kingsport, Tenn.); phosphate ester (flameretardant) (FYROL A710, available from ICL Industrial Products, of St.Louis, Mo.); isopropylated triaryl phosphate ester (phosphorous flameretardant) (REOFOS 35, available from Lanxess Aktiengesellschaft, ofCologne, Germany); cresyl diphenyl phosphate (flame retardant) (KRONITEXCDP, available from Lanxess Aktiengesellschaft, of Cologne, Germany);antimony trioxide (flame retardant performance enhancer) (AMSPEC SELECT,available from Amspec Chemical Corporation, of Gloucester City, N.J.);modified urea solution (rheology additive/anti-settling agent) (BYK-410,available from BYK USA Inc., of Wallingford, Conn.); modified liquid MDI(isocyanate—29% NCO) (ISONATE 143L, available from The Dow ChemicalCompany, of Midland, Mich.); polymeric MDI (2.7 functionality) (RUBINATEM, available from Huntsman Corporation, of The Woodlands, Tex.).

The compositions were made and tested according to the test methodsdescribed above. The results and observations are set forth in Table 1.

TABLE 1 Sample Compositions and Measured Results Comparative ComparativeExample 1 Example 2 Sample 1 Sample 2 Component A Materials (wt. %) 2000M_(n) PPG diol polyether polyol 94.0 43.0 10.0 10.0 Glycerin 99.5% 1.003.00 3.00 3.00 Triethanolamine 99% 1.50 2.00 2.50 2.50 Fumed silica 1.001.00 0.50 0.50 Zinc stearate 1.00 1.00 1.00 1.00 Zinc borate FR 0.000.00 0.00 0.00 Ethylenebistetrabromophthalimide 0.00 0.00 0.00 0.00Distilled Water 0.50 1.20 1.20 1.20 Tertiary amine catalyst (DABCO 33LV)0.50 0.15 0.08 0.08 Titanium dioxide 0.50 0.50 0.95 0.95 Tertiary aminecatalyst (DABCO 8154) 0.00 0.00 0.00 0.00 700 M_(n) PPG triol polyol(Poly G 30-240) 0.00 43.15 40.0 40.0 280 M_(n) PPG tetra polyol(VORANOL) 0.00 2.00 2.00 2.00 Silicone surfactant (DC 5160) 0.00 3.003.00 3.00 Halogenated phosphate ester FR 0.00 0.00 32.00 0.00 Trimethylpentanyl diisobutyrate 0.00 0.00 3.77 3.77 Phosphate ester FR (FYROLA710) 0.00 0.00 0.00 32.0 Isopropylated triaryl phosphate ester 0.000.00 0.00 0.00 Cresyl diphenyl phosphate FR 0.00 0.00 0.00 0.00 Antimonytrioxide 0.00 0.00 0.00 0.00 Modified urea solution 0.00 0.00 0.00 0.00Total 100 100 100 100 Viscosity @ 25° C. (cP) 1500 800 400 350 ComponentB Materials (wt. %) Modified liquid MDI - 29% NCO 100 0.00 0.00 0.00Polymeric MDI - 2.7 functionality 0.00 100 100 100 Phosphate ester FR(FYROL PCF) 0.00 0.00 0.00 0.00 Total 100 100 100 100 Viscosity @ 25° C.(cP) 40 200 200 200 Mix Ratio by Weight (100 g of A = X g of B) 29 67 6060 Percent Flame Retardant in Final Blend 0% 0 20 20 FlowabilityAcceptable Good Very Very Good Good Foam Density (lbs/ft³) 15 8 9 9.9Foam Density (g/cm³) 0.24 0.13 0.14 0.16 Foam Hardness after 24 hrs RT(Shore A) 6 40 30 Burn Results @ Indicated Thickness All All 9.5 mm =9.5 mm = (UL 94 vertical) Thickness Thickness Fail Fail Fail Fail Sample3 Sample 4 Sample 5 Sample 6 Component A Materials (wt. %) percent) 2000M_(n) PPG diol polyether polyol 10.0 10.0 0.00 0.00 Glycerin 99.5% 3.003.00 3.00 3.00 Triethanolamine 99% 2.50 2.50 3.00 3.00 Fumed silica 0.500.50 1.00 1.00 Zinc stearate 1.00 1.00 1.00 1.00 Zinc borate FR 0.000.00 1.00 1.00 Ethylenebistetrabromophthalimide 0.00 0.00 0.00 0.00Distilled Water 1.20 1.20 1.20 1.20 Tertiary amine catalyst (DABCO 33LV)0.08 0.08 0.05 0.05 Titanium dioxide 0.95 0.95 0.00 0.00 Tertiary aminecatalyst (DABCO 8154) 0.00 0.00 0.00 0.00 700 M_(n) PPG triol polyol40.0 40.0 36.0 36.0 280 M_(n) PPG tetra polyol 2.00 2.00 3.00 3.00Silicone surfactant (DC 5160) 3.00 3.00 2.50 2.50 Halogenated phosphateester FR 0.00 0.00 48.0 48.0 Trimethyl pentanyl diisobutyrate 3.77 3.770.00 0.00 Phosphate ester FR (TYROL A710) 0.00 0.00 0.00 0.00Isopropylated triaryl phosphate ester FR 32.0 0.00 0.00 0.00 Cresyldiphenyl phosphate FR 0.00 32.0 0.00 0.00 Antimony trioxide 0.00 0.000.25 0.25 Modified urea solution 0.00 0.00 0.00 0.00 Total 100 100 100100 Viscosity @ 25° C. (cP) 350 400 675 625 Component B Materials (wt.%) Modified liquid MDI - 29% NCO 0.00 0.00 0.00 0.00 Polymeric MDI - 2.7functionality 100 100 100 55 Phosphate ester FR (FYROL PCF) 0.00 0.000.00 45 Total 100 100 100 100 Viscosity @ 25° C. (cP) 200 200 200 145Mix Ratio by Weight (100 g of A = X g of B) 60 60 60 108 Percent FlameRetardant in Final Blend 20 20 30 46.4 Flowability Very Very Very VeryGood Good Good Good Foam Density (lbs/ft³) 9.6 9.8 7.2 11.7 Foam Density(g/cm³) 0.15 0.16 0.12 0.19 Foam Hardness after 24 hrs RT (Shore A) — —35 35 Burn Results @ Indicated Thickness 9.5 mm = 9.5 mm = 9.5 mm = 9.5mm = (UL 94 vertical) Fail Fail V1 V0 Sample 7 Sample 8 Sample 9 Sample10 Component A - Materials (wt. %) 2000 M_(n) PPG diol polyether polyol0.00 0.00 0.00 0.00 Glycerin 99.5% 3.00 3.00 3.10 3.20 Triethanolamine99% 3.00 3.00 2.90 2.90 Fumed silica 0.70 0.70 0.70 0.70 Zinc stearate1.00 1.00 1.00 1.00 Zinc borate FR 0.00 0.00 0.00 0.00Ethylenebistetrabromophthalimide 1.00 1.00 1.00 1.00 Distilled Water1.30 1.30 1.30 1.30 Tertiary amine catalyst (DABCO 33LV) 0.05 0.05 0.050.02 Titanium dioxide 0.00 0.00 0.00 0.00 Tertiary amine catalyst (DABCO8154) 0.00 0.00 0.00 0.01 700 M_(n) PPG triol polyol 36.0 36.0 36.1 36.4280 M_(n) PPG tetra polyol 3.00 3.00 2.90 2.80 Silicone surfactant (DC5160) 2.50 2.50 2.50 0.55 Halogenated phosphate ester FR 47.2 47.2 47.248.9 Trimethyl pentanyl diisobutyrate 0.00 0.00 0.00 0.00 Phosphateester FR (FYROL A710) 0.00 0.00 0.00 0.00 Isopropylated triarylphosphate ester 0.00 0.00 0.00 0.00 Cresyl diphenyl phosphate FR 0.000.00 0.00 0.00 Antimony trioxide 1.00 1.00 1.00 1.00 Modified ureasolution 0.30 0.30 0.30 0.30 Total 100 100 100 100 Viscosity @ 25° C.(cP) 437 425 362 360 Component B - Materials (wt. %) Modified liquidMDI - 29% NCO 0.00 0.00 0.00 0.00 Polymeric MDI - 2.7 functionality 7080 70 70 Phosphate ester FR (FYROL PCF) 30 20 30 30 Total 100 100 100100 Viscosity @ 25° C. (cP) 162 180 160 160 Mix Ratio by Weight (100 gof A = X g of B) 86 76 86 87 Percent Flame Retardant in Final Blend 39.735.8 39.7 40 Flowability Very Very Very Very Good Good Good Good FoamDensity (lbs/ft³) 8.9 8.3 9.7 10 Foam Density (g/cm³) 0.14 0.13 0.160.16 Foam Hardness after 24 hrs RT (Shore A) 40 40 35 40 First BurnResults @ Indicated Thickness 9.5 mm = 9.5 mm = 9.5 mm = 9.5 mm = (UL 94vertical) V0 V0 V0 V0 Second Burn Results @ Indicated Thickness 0.000.00 6.35 mm = 6.35 mm = (UL 94 vertical) V0 V0

Samples 11 to 14, were prepared with a similar process as described forSamples 1 to 10. Samples 11 to 14 were prepared with the followingcomponents, given with the trade designation and supplier whereapplicable, and in the amounts set forth in Table 2: glycerin 99.5%(triol crosslinker/humectant) (available from the Dow Chemical Company,of Midland, Mich.); triethyanolamine 99% (triolcrosslinker/humectant/catalyst) (available from the Dow ChemicalCompany, of Midland, Mich.); fumed silica (thixotrop) (TS-720, availablefrom the Cabot Corp., of Boston, Mass.); zinc stearate (nucleatingagent) (NB-60, available from PMC Group, of Memphis Tenn.);ethylenebistetrabromophthalimide (brominated flame retardant) (SAYTEXBT-93, available from Albemarle Corporation, of Baton Rouge, La.);distilled water (foam blowing agent); 1,4-Diazabicyclo[2.2.2]octanesolution ((first) tertiary amine catalyst) (DABCO 33 LV, available fromEvonik Industries, of Essen, Germany); (second) tertiary amine catalyst(DABCO DMDEE, available from Evonik Industries, of Essen, Germany); 700M_(n) PPG triol polyol) (low viscosity polyol) (POLY G 30-240, availablefrom Monument Chemical Group, of Houston, Tex.); 280 M_(n) amine/PPGtetra polyol (tetra crosslinker/humectant/catalyst) (VORANOL 800,available from The Dow Chemical Company, of Midland, Mich.); siliconesurfactant (foam cell surfactant) (VORASURF DC 5160, available from theDow Chemical Company); halogenated phosphate ester (flame retardant)(FYROL PCF, available from ICL Industrial Products, of St. Louis, Mo.);silicone surfactant (EPH 190, available from Evonik industries); diamine(curing agent) (LONZACURE DETDA 80, available from Lonza, Inc., ofAllendale, N.J.); antimony trioxide (flame retardant performanceenhancer) (AMSPEC SELECT, available from Amspec Chemical Corporation, ofGloucester City, N.J.); modified urea solution (rheologyadditive/anti-settling agent) (BYK-410/BYK-430, available from BYK USAInc., of Wallingford, Conn.); fumed silica (TS-720); polymeric MDI (2.7functionality) (RUBINATE M, available from Huntsman Corporation, of TheWoodlands, Tex.); halogenated phosphate ester (FYROL PCF): siliconesurfactant (VORASUF DC 5098, available from, the Dow Chemical Company).

The compositions were made and tested according to the test methodsdescribed above. The results and observations are set forth in Table 2.

TABLE 2 Sample Compositions and Measured Results Sample 11 Sample 12Sample 13 Sample 14 Component A - Materials (wt. %) Glycerin 99.5% 2.002.00 2.00 3.20 Triethyanolamine 99% 2.40 2.40 2.40 2.85 Fumed silica4.25 4.25 4.25 5.00 Zinc stearate 0.70 0.70 0.70 0.70 Brominated FR 1.001.00 1.00 1.00 Distilled water 1.90 2.20 2.20 1.50 Tertiary aminecatalyst (DABCO 33LV) 0.010 0.015 0.015 0.010 Tertiary amine catalyst(DABCO DMDEE) 0.010 0.015 0.015 0.010 700 M_(n) PPG triol polyol 36.236.3 36.3 36.5 280 M_(n) amine/PPG tetra polyol 2.40 2.40 2.40 2.80Silicone surfactant (DC 5160) — — — 0.40 Halogenated phosphate ester FR43.4 42.6 42.7 44.7 Silicone surfactant (EPH 190) 1.50 1.75 1.75 —Diamine curing agent 3.00 3.00 3.00 — Antimony trioxide 1.00 1.00 1.001.00 Modified urea solution 0.30 0.40 0.30 0.30 Total 100 100 100 100Part A Viscosity @ 25° C. (cps) 12950 12000 12800 17200 Component B -Materials (wt. %) Fumed Silica 2.80 2.80 2.80 6.00 Polymeric MDI - 2.7funct. 67 67 67.0 67.0 Halogenated phosphate ester FR 30 30 30. 27.0Silicone surfactant (DC 5098) 0.20 0.20 0.20 — Total 100 100 100 100Viscosity @ 25 C. (cps) 5262 5000 5200 9825 Mix Ratio by Weight (100 gmof A = X g of B) 93 96 96 86 Percent Flame Retardant in Final Blend 37.436.9 36.9 37.1 Foam Density (lbs/ft³) 10.50 7.80 9.0 9.5 Foam Density(g/cm³) 0.17 0.13 0.14 0.15 First Burn Results @ Indicated Thickness6.35 mm = 6.35 mm = 6.35 mm = 6.35 mm = (UL 94 vertical) V0 V0 V0 V0

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the above described features.

What is claimed is:
 1. A battery module comprising: an electric cellpotted in a potting compound; the potting compound comprising a curedmixture of a flame retardant component; a first component having anisocyanate reactive compound and water; and a second component having anisocyanate compound, wherein the potting compound is a foam.
 2. Thebattery module of claim 1, wherein the potting compound has at least aV2 level flame resistance as measured by the UL 94 Test for Flammabilityof Plastics.
 3. The battery module of claim 1, wherein the firstcomponent has a viscosity from greater than one to less than 100,000 cP,and wherein the second component has a viscosity from greater than oneto less than 50,000 cP, all at a temperature from about 25° C. to about35° C.
 4. The battery module of claim 1, wherein the first component hasa viscosity from greater than one to less than 1500 cP, and wherein thesecond component has a viscosity from greater than one to less than 1000cP, all at a temperature from about 25° C. to about 35° C.
 5. Thebattery module of claim 1, wherein the potting compound has a foamdensity of less than 0.50 g/cm³.
 6. The battery module of claim 1,wherein the flame retardant component is present in an amount of atleast 15 wt. %, based on the total weight of the potting compound. 7.The battery module of claim 1, wherein the flame retardant component ispresent in an amount of at least 30 wt. %, based on the total weight ofthe potting compound.
 8. The battery module of claim 1, wherein theflame retardant component is a liquid.
 9. The battery module of claim 1,wherein the battery module includes a plurality of electric cells, eachelectric cell having a bottom, a top, and a length defined therebetweenthe potting compound being at a substantially level height.
 10. Abattery module comprising: an electric cell potted in a potting compoundcomprising a reaction product of a first component having an isocyanatereactive compound; a second component having an isocyanate compound; anda blowing agent; and a liquid flame retardant component present in anamount from about 15 wt. % to about 60 wt. % based on the total weightof the potting compound.
 11. The battery module of claim 10, wherein theliquid flame retardant includes a phosphate ester.
 12. The batterymodule of claim 10, wherein the first component has a viscosity fromgreater than one to less than 100,000 cP, and wherein the secondcomponent has a viscosity from greater than one to less than 50,000 cP,all at a temperature from about 25° C. to about 35° C.
 13. The batterymodule of claim 10, wherein the isocyanate reactive compound has anisocyanate reactive functionality of three or more.
 14. The batterymodule of claim 10, wherein the isocyanate compound has an isocyanatefunctionality of two or greater.
 15. The battery module of claim 10,wherein the potting compound further includes at least one of acrosslinking catalyst, a nucleating agent, a surfactant, or aflame-retardant enhancer, and combinations thereof.
 16. The batterymodule of claim 10, wherein the potting compound has at least a V2 levelflame resistance as measured by the UL 94 Test for Flammability ofPlastics.
 17. The battery module of claim 10, wherein the pottingcompound has a density of less than 0.50 g/cm³.
 18. The battery moduleof claim 10, wherein the battery module includes a plurality of electriccells, each electric cell having a bottom, a top, and a length definedtherebetween, the potting compound being at a substantially levelheight.
 19. A battery module comprising: a first electric cell potted ina polyurethane foam potting compound, wherein the potting compound has adensity of less than 0.50 g/cm³, and wherein the potting compound has atleast a V2 level flame resistance as measured by the UL 94 Test forFlammability of Plastics.
 20. The battery module of claim 19, whereinthe battery module includes a plurality of electric cells, each electriccell having a bottom, a top, and a length defined therebetween, thepotting compound being at a substantially level height.
 21. The batterymodule of claim 19, wherein the potting compound includes a liquid flameretardant component in an amount of at least 15% by weight, based on thetotal weight of the potting compound.
 22. A battery module comprising: apolyurethane foam potting compound; and an electric cell potted in thepotting compound; the polyurethane foam potting compound including aliquid flame retardant component in an amount of at least 15% by weight,based on the total weight of the potting compound.
 23. The batterymodule of claim 22, wherein the battery module includes a plurality ofelectric cells, each electric cell having a bottom, a top, and a lengthdefined therebetween, the potting compound being at a substantiallylevel height.